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uitrit -tstes atrnt @fitta THEO DORE THURBER, OF AUBURN, NEW YORK.

Leampaant No. 63,185, @zaad March 26, 1867.

IMPROVEMENT IN PIS'I'ON PACKING.

T0"ALL WHOM IT MAY CONCERN:

Be it known that I, TIIEODORE THURBER, of Auburn, in the county of Cayuga, State of New York, have invented certain new and useful improvements in a. Self-Regulating Equilibrium Pressurel Packing Piston for steam cylinders, gas or water engines, pumps, &c., and the followingis a full, clear, and exact description of the same, reference being had to the accompanying drawings, making a part of this specification, in which- Figure 1 represents a cross-section through the 4piston head, showing the metal packing-ring, internal flange-plate. ring-cap, the two valves for admitting the steam, gas, or Water into the recess, to press equally on the entire inner' surface of the packing-ring, andthe spiralspring, to hold the valves off their seat when no pressure is on them.

Figure 2 shows a plan or top view of the spideror skeleton-head with the end cap removed.

Figure 3 is an enlarged detached view of valves. i

The object of my invention Vis to introduce'the most simple, cheap, anddurable-selffpressure regulating 'metallic piston packing for locomotive `and other engines,hy which the pressure under thepacking-ring oi' the piston is reduced from fifty to seventy per cent. per inch less than thepressure in the boiler, and `this reduced pressure being kept uniform the whole length ofthe stroke, thereby making the wear uniform the entire length of the cylinder, which is not the case with other steam packing not so regulated.

My invention consists in `the construction of the internal flange-plate A, ring-cap B, between which the packing-ring C may be placed without expanding, they forming anarrow, steam-tight recess, a a, surrounding the iston. Also, in the arraneem'ent of two double-faced valves e e, actinrr Aon one s irai s rinooZ, ev uallv p C) D p p C), q n/ by the pressure on either side of the piston, so that the steam, gas, or water forced into the recess a a is not' exhausted at cach stroke, the internal pressure on the packing-ring C being regulated by and is equal to the force of the spring cZ that holds the valves e e to their seats inside of the recess.

To enable others to make and use my invention, I will describe it more fully in its construction and operation.

The spider-plate E, the internal {lange-plate-A, ring-cap B, and face-platel? are the most plain and simple iron castings, which are easily turned olf-and fitted in a common engine lathe. The metal packing-ring C may be forged of steel or may be cast of other` metal, and fitted in the same manner. In both the flange-plate Aand the ring-cap B are the seats for the-small cone valves e e, which have stems, ff, and a shoulder, z' ,to bear on theinsideof the rings and rest on the spiral springs d which may be of any required capacity 'to allow the pressure from either side of the piston H through the small orifice h to act on the valves e e, thus admitting as much force ,of steam, gas, or water into the recess a a as the resistance ofthe spring d will yield to, and then the apertures are closed by the cone valvesee, and kept so aslong as the pressure outside in the cylinder is greater than the resistance ofthe spring d, so that the force in the'recess a a, which acts directly and equally againstthe entire surface ofthe met-al ring packing C, is kept uniform in the same ratio of from fifty to seventy per cent. per inch less than the pressure in the cylinder or boiler, this being obtained by the area or opening around the stem between the two faces ofthe valves e e, together with the distance or space in which the valves move. Other advantages to bederived by a steam piston packing from which the steam is not exhausted from under the packing-ring at each stroke, are, that the piston in vertical or beam .engines maybe retained in any desired position when stopped, so as to enable thc engine to be started back or forward without the necessity of bringingthe piston to near the centre ofthe cylinder, as would be the case when allowed to exhaust; or, by a greater weight on either crank or piston to cause thc same to approach eitherl head of the ycylinder during the haltv 'or ordinary stopping of marine engines. It has been -practically demonstrated that a very large percentage of' the power is saved by the means above described over any other mode of metallic packing for pistons known and used.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. The construction of the internal ring-plate A, with ring-caps Blitted, leaving a steam chamber or irecess, a, between them and the metal ring packing C, so .that it can be put in its place without opening or expanding, substantially4 as described.

2. I claim the' two valves 'c e as constructed, in combination with the ring-plate and cap B, operating lfrom both sides or faces ofthe piston, they beingv supported by the spring d, so that steam, gas. or water forced into the chambera is not exhausted or liberated at each stroke, -thc internal force being retained, thereby produoin'gthe result, substantially as herein speci'ed.

3. I claim the combination of the skeleton frameand plate 1l, flange-plate A, ring-cap B, faceplate F, metal packing-'ring C, valves e e, and spiral spring d, all constructed and arranged to operate substantially as. and for the purposes herein'set forth. i Y

' THEODORE THURBER.

Witnesses:

JOHN S. HoLLINGsHsam WM. J. FAHEMY. 

